/Engine/Source/Runtime/Engine/Classes/EditorFramework/AssetImportData.h
InPath: The filename we want to set at the specified index.Index: This specify the source file index in case you have many source file for an imported asset  SourceFileLabel: Optional, can be empty string, the label we want to see in the UI when displaying the source file. (useful for multi source)
void ScriptedAddFilename ( const [FString](API\Runtime\Core\Containers\FString) & InPath, int32 Index, [FString](API\Runtime\Core\Containers\FString) SourceFileLabel )